MAN B&W 5L28/32H, Manual

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08028-0D\H5250\94.08.12
Internal Cooling Water System B 13 00 0
Internal Cooling Water System
The engine's cooling water system comprises a low
temperature (LT) circuit and a high temperature (HT)
circuit.
Low Temperature Cooling Water System
The LT cooling water system includes charge air
cooling, lubricating oil cooling and alternator cooling
if the latter is water-cooled. The LT system is de-
signed for freshwater (FW) as cooling medium.
Seawater (SW) can be used as optional.
In order to prevent a too high charge air temperature,
the design freshwater temperature in the LT system
should not be too high Max. 36°C is a convenient
choice compared to the design for seawater tem-
perature of maximum 32°C.
Regarding the lubricating oil cooler, the inlet tempe-
rature of the LT cooling water should not be below
10°C.
High Temperature Cooling Water System
The high temperature cooling water is used for the
cooling of cylinder liners and cylinder heads.
An engine outlet temperature of 80°C ensures a
perfect combustion in the entire load area when
running on Heavy Fuel Oil (HFO), i.e. this tempe-
rature limits the thermal loads in the high-load area,
and hot corrosion in the combustion area is avoided.
In the low-load area, the temperature is sufficiently
high to secure a perfect combustion and at the same
time cold corrosion is avoided; the latter is also the
reason why the engine, in stand-by position and
when starting on HFO, should be preheated with a
medium cooling water temperature of at least 60°C
- either by means of cooling water from running
engines or by means of a separate preheating
system.
System Lay-Out
MAN B&W Holeby's standard for the internal cooling
water system is shown on Basis Diagram 2. The
system has been constructed with a view to full
integration into the external system.
Temperature regulation in the HT and LT systems
takes place in the external system where also pumps
and freshwater heat exchangers are situated. This
means that these components can be common for
propulsion engine(s) and GenSets. The separation
of HT and LT circuits means that the cooling medium
for the LT system can be either SW or FW, so that
Basis System 2 can match a conventional as well as
a central cooling water system.
To be able to match every kind of external systems,
the internal system can as optional be arranged with
two separate circuits or as a single circuit with or
without a built-on pump and a thermostatic valve in
the HT-circuit, so that engine cooling can be inte-
grated fully or partly into the external system, or can
be constructed as a stand-alone unit.
Different internal basis system layouts for these
applications are shown on the following pages.
HT-Circulating Pumps
The circulating pump which is of the centrifugal type
is mounted on the front cover of the engine and is
driven by the crankshaft through a resilient gear
transmission.
Technical data : See "list of capacities" D 10 05 0
and B 13 18 1-2.
Thermostatic Valve
The termostatic valve is a fully automatic three-way
valve with thermostatic elements set at fixed tem-
perature.
Technical data: See B 13 15 1.
95.09
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General